1. Field of the Invention
The present invention relates to a wireless communication system and, more particularly, to a method of reporting, by user equipment, system information in a wireless communication system and an apparatus for supporting the same.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) which is improvement of a universal mobile telecommunications system (UMTS) is introduced as 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. Multiple input multiple output (MIMO) having maximum four antennas are adopted. In recent years, 3GPP LTE-advanced (LTE-A) which is an evolution of the 3GPP LTE has been discussed.
A closed subscriber group (CSG) allows a limited access for only a specific subscriber to be introduced to provide a service having higher quality. A base station that can provide a CSG service may be home eNodeB (HNB) and a cell providing an authorized service to CSG subscribers may be a CSG cell. In the 3GPP, a basic requirement of the CSG is disclosed in 3GPP TS 22.220 V1.0.1 (2008-12) “Service requirements for Home NodeBs and Home eNodeBs (Release 9)”.
A feature of a CSG cell restrictedly providing the service is illustrated even in handover to the CSG cell. Whether a user equipment (UE) is a CSG member of a corresponding cell may be problematic in performing the handover to the CSG cell. As a result, the handover to the CSG cell may be implemented by a first step in which the UE reports a cell measurement result and a second step in which the UE acquires system information from a target cell and reports the acquired system information to a service cell.
When a message that instructs UE to report system information about a neighboring cell is received from a serving cell, the UE accesses the neighboring cell and obtains the system information. The UE sends the obtained system information to the serving cell. While the UE accesses the neighboring cell in order to obtain the system information, the serving cell is unable to send any command/message/data to the UE.
Meanwhile, the UE may obtain the system information about the neighboring cell before being instructed by the serving cell to report the system information. Even in such a case, a step of leaving, by the UE, the serving cell and accessing the neighboring cell in order to newly obtain the system information about the neighboring cell may be unnecessary, if necessary. Accordingly, there is a need for a more efficient method of reporting, by UE, system information.